Plasmonic optical fibers, plasmonic optical sensors and methods of manufacturing the same. A fiber core conveys an optical signal therewithin and provides a plasmonic sensing area exposed to a fluid. The plasmonic sensing area is formed only on a section of an external surface of the fiber core. The plasmonic sensing area provides an interface within the section of the external surface for the conveyed signal to at least partially exit the fiber core and cause a modified optical signal to be conveyed in the fiber core. An optical signal generator may provide the optical signal to the plasmonic optical fiber, an optical signal receiver may discriminate the conveyed optical signal from the modified optical signal and a processor module may analyze the modified optical signal and identifies physical characteristics of the fluid present at the sensing area.

A fiber optic sensor interrogation system with inbuilt passive power limiting capability based on stimulated Brillouin scattering that provides improved safety performance for use in explosive atmospheres.

A method for detecting defects in a composite structure, such as in an aircraft structure, that includes sending an optical signal down an optical fiber embedded in the composite structure and analyzing the optical signal at a detector. If it is determined that the optical signal is turning on and off or an increase in the bit error rate is occurring at the detector, the composite structure may be delaminating or the composite structure may be somehow damaged. If it is determined that the composite structure is damaged, the optical signal can be sent down a different optical fiber that may not be at a location where the composite structure is damaged, and a continuous beam of light can be sent down the optical fiber that is at the damaged part of the composite structure to determine whether the damage is increasing.

A method and a device allow optical properties of a sample to be estimated. The method includes the illumination of the sample by a first light source, and the formation of an image of the sample thus illuminated, on the basis of which a first optical property is estimated, at various points on a surface of the sample. The method also includes measuring an auxiliary optical property of the sample and estimating the first optical property, taking account of the auxiliary optical property measured on the sample.

An in-situ on-line detection device and detection method for a long-distance metallurgical liquid metal component. The detection device comprises a front-end high-temperature resistant probe, a middle-end optical sensing device and a back-end control platform, wherein the head of the front-end high-temperature resistant probe is placed in a liquid metal, the tail thereof is coaxially connected to the middle-end optical sensing device, and an optical window is arranged in the connection position; and the middle-end optical sensing device is connected to the back-end control platform through a signal line. The detection device and detection method can provide a timely and valid message for quality control and a melting end, so that the detection time is greatly shortened, the detection distance can he adjusted extensively, the measurement result is accurate, and it can be achieved to measure components that are difficult to measure such as carbon, sulfur, phosphorous, etc.

A method and device for monitoring oil field operations with a fiber optic distributed acoustic sensor (DAS) that uses a continuous wave laser light source and modulates the continuous wave output of the laser light source with pseudo-random binary sequence codes.

An optical sensor and method of manufacture are provided herein. The optical sensor includes an optical fiber comprising a terminating end surface, and a photonic crystal coupled to the terminating end surface of the optical fiber.

A solution is provided comprising boron nitride nanotubes (BNNTs) in a liquid solvent. An optical waveguide, such as an optical fiber, is contacted with the solution so as to form a layer of the solution supported on at least a portion of the optical waveguide. The liquid solvent is then removed from the layer of the solution supported on the optical waveguide in order to form a coating of the BNNTs on the optical waveguide. Further provided is a BNNT coated optical waveguide for use as a sensor.

The present invention provides a tapered side-polished fiber-optic biosensor (FOBS) and a method for preparing a tapered side-polished fiber (SPF). The biosensor includes a broadband light source, a first single-mode fiber, a tapered SPF, a second single-mode fiber, and a spectrometer. The broadband light source is connected to the tapered SPF through the first single-mode fiber, and the tapered SPF is connected to the spectrometer through the second single-mode fiber. The broadband light source is configured to emit a light wave. The spectrometer is configured to display a spectrum corresponding to a light wave passing through the first single-mode fiber, the tapered SPF, and the second single-mode fiber successively. In the present invention, a fiber side-polishing technology is combined with a fiber tapering technology to construct a tapered SPF, and a spectrum changes by changing a refractive index around a side-polished tapered region, thereby measuring the refractive index. In addition, the tapered SPF provided in the present invention can generate a Vernier effect, thereby improving the sensor's anti-electromagnetic interference and sensitivity to refractive index measurement.

Systems, methods, and techniques for optofluidic analyte detection and analysis using multi-mode interference (MMI) waveguides are disclosed herein. In some embodiments, spatially and spectrally multiplexed optical detection of particles is implemented on an optofluidic platform comprising multiple analyte channels intersecting a single MMI waveguide. In some embodiments, multi-stage photonic structures including a first stage MMI waveguide for demultiplexing optical signals by spatially separating different wavelengths of light from one another may be implemented. In some embodiments, a second stage may use single-mode waveguides and/or MMI waveguides to create multi-spot patterns using the demultiplexed, spatially separated light output from the first stage. In some embodiments, liquid-core MMI (LC-MMI) waveguides that are tunable by replacing a liquid core, heating/cooling the liquid core, and/or deforming the LC-MMI to change its width may be implemented in one or more of the analyte detection/analysis systems disclosed herein.